Elective surgery and resulting blood loss are often associated with increases in insulin resistance of magnitudes of 50% or greater following uncomplicated surgical operations (Thorell, Anders, Nygren, Jonas; Ljungqvist, Olle. Insulin resistance: a marker of surgical stress. Curr Opin Clin Nutr Metab Care 2:69-78, 1999). It is not clear which mediators are most crucial for the development of insulin resistance following surgery and hemorrhage. Hemorrhage is a useful model of acute stress because it can be quantified in anaesthetized animals and results in a wide range of metabolic consequences including hyperglycemia and insulin resistance (Ma, Y., Want, P., Kuebler, J. F., Chaudry, I. H., Messina, J. L. Hemorrhage induced the rapid development of hepatic insulin resistance. Am J Physiol Gastrointest Liver Physiol.: 284: G107-G115, 2002).
Elevations in plasma glucose levels following rapid blood loss are mediated primarily through the hepatic sympathetic nerves and the adrenals (Lautt, W. W., Dwan, P. D., Singh, R. R. Control of the hyperglycemic response to hemorrhage to cats. Can J Physiol Pharmacol. 60:1618-1623, 1982). The activation of this redundant control system in response to hemorrhage initiates several compensatory responses, with the most crucial being glycogenolysis and insulin level reduction (Hiebert, J. M., J. M. McCormick, R. H. Egdahl. Direct measurement of insulin secretory rate: studies in shocked primates and postoperative patients. Ann. Surg: 176:296-304, 1972. Hiebert, J. M., C. Kieler, J. S S S. Soldner, R. H Egdahl. Species differences in insulin secretory response during hemorrhagic shock. Surgery: 79:451-455, 1976). The attenuation in insulin levels following hemorrhage are physiologically advantageous, as glucose can be utilized for life-sustaining systems and osmotic mobilization of extravascular fluid into the circulation (Yamaguchi, N. Sympathoadrenal system in neuroendocrine control of glucose: mechanisms involved in the liver, pancreas, and adrenal gland under hemorrhagic and hypoglycemic stress. Can J Physiol Pharmacol. 70(2):167-206, 1992). Thus, survival following a severe hemorrhage is closely related to the capacity of the animal to develop hyperglycemia (Nettelbladt, C. G., Aligobevic, A., Ljungqvist, O., Pre-stress carbohydrate solution prevents fatal outcome after hemorrhage in 24 hour food deprived rats. Nutrition 12:10:696-699, 1996).
The present inventors have recently described a novel mechanism of insulin resistance. Postprandial insulin causes the release of a Hepatic Insulin Sensitizing Substance (HISS), which acts selectively on skeletal muscle to stimulate glucose uptake. HISS-dependent insulin action accounts for approximately 55% of total insulin action in the fed state (Lautt W. W., Macedo M P, Sadri, P., Takayama, S., Ramos, F. D., Legare, D. J. Hepatic parasympathetic nerve-dependent control of peripheral insulin sensitivity is determined by feeding and fasting: dynamic control of HISS-dependent insulin action. Am J Physiol. Gastrointest. Liver Physiol. 281:G29-G36, 2001). The blockade of HISS release or action leads to a state of insulin resistance known as HISS-dependent insulin resistance (HDIR). HDIR is seen in a wide variety of pathological models including; fasting (Lautt et al., 2001), hepatic muscarinic cholinergic blockade with atropine (Xie, H. and Lautt, W. W. Induction of insulin resistance by cholinergic blockade with atropine in the cat. J. Auton. Pharmacol. 15:361-369, 1995. Xie, H. and Lautt, W. W. Insulin resistance produced by hepatic denervation or muscarinic cholinergic blockade. Proc. West. Pharmacol. Soc. 37:39-40, 1994), hepatic nitric oxide synthase blockade with L-NMMA or L-NAME (Sadri, P. and Lautt, W. W. Blockade of hepatic nitric oxide synthase causes insulin resistance. Am. J. Physiol. 277:G101-G108, 1999. Sadri, P. and Lautt, W. W. Blockade of nitric oxide production in the liver causes insulin resistance. Proc. West. Pharmacol. Soc. 41:37-38, 1998), hepatic cyclooxygenase inhibition (Sadri, P. and Lautt W. W. Insulin resistance caused by hepatic COX inhibition. Diabetes: 49(Suppl 1):A245, 2000), or surgical denervation of the liver (Xie, H. and Lautt, W. W. Insulin resistance produced by hepatic denervation or muscarinic cholinergic blockade. Proc. West. Pharmacol. Soc. 37:39-40, 1994. Latour, M. G. and Lautt, W. W. The hepatic vagus nerve in the control of insulin sensitivity in the rat. Autonomic Neurosci. 80:8-12, 2002). HDIR has been suggested to account for postprandial hyperglycemia, hyperinsulinemia, and hyperlipidemia (Lautt, W. W., A new paradigm for diabetes and obesity: The hepatic insulin sensitizing substance (HISS) hypothesis. J. Pharmacol. Sci. 95:9-17, 2004). Most recently, the present inventors have shown that hemorrhage demonstrates insulin resistance that is totally accountable for by HDIR. (Seredycz, L., Ming, X., Lautt, W. W. Acute hemorrhage causes HISS-dependent insulin resistance. Submitted to the American Journal of Physiology in 2004).
The response to stress and surgical trauma has been described as a multi-hormonal reaction that is designed to act in a selective manner specific to the stimulus imposed upon it (Mason, J. W., Wherry, F. E., Pennington, L. L., Spector, N. H. A historical view of the stress field. J. Human Stress. March; 1(1):6-12, 1975). Regulators of the hemorrhagic response that induce HDIR may include the hepatic sympathetic nerves and the endocrine system. The blockade of alpha and beta hepatic receptors may assist in the prevention of HDIR following hemorrhage as adrenergic stimulation is partially responsible for the regulation of insulin and glucagon release in response to stress, and may regulate the basal secretion of insulin (Robertson, R. P., Porte, D. Adrenergic modulation of basal insulin secretion in man. Diabetes 1973; 22:1-8). Somatostatin, a poorly understood hormone, is a potent inhibitor of insulin and glucagon and may also play a key role in initiating HDIR, as levels in cats are shown to increase dramatically following hemorrhage (Lautt, W. W., Dwan, P. D., Singh, R. R. Control of the hyperglycemic response to hemorrhage to cats. Can J Physiol Pharmacol. 60:1618-1623, 1982).